ICEINSPACE
Most Read Articles
Moon Phase
CURRENT MOON Waxing Gibbous
91.4%
The Sun Now
Time Zones
Sydney
12:29 pm
Perth
10:29 am
Auckland
2:29 pm
New York*
10:29 pm
Paris*
4:29 am
GMT
2:29 am




Go Back   IceInSpace > Equipment > DIY Observatories

Reply
 
Thread Tools Rate Thread
  #1  
Old 08-03-2018, 06:12 PM
SimmoW's Avatar
SimmoW (SIMON)
Adapter Collector

SimmoW is offline
 
Join Date: Jan 2014
Location: Tamleugh, Victoria, Australia
Posts: 1,273
Cages on piers?

Hi folks, I'm thinking of getting a pier custom built by a trusted contact.

Many ppl use a cage to fine tune levelling. This concerns me due to possible flexure. Are my concerns valid? Is it possible to have a perfectly horizontal base? Does it matter nowadays if it's not perfectly level?

Thanks in anticipation of any comments/ideas.
Reply With Quote
  #2  
Old 08-03-2018, 06:16 PM
Lognic04's Avatar
Lognic04 (Logan)
Registered User

Lognic04 is offline
 
Join Date: Mar 2016
Location: Melbourne, VIC
Posts: 640
Levelling is not important at all for an equatorial mount because you polar align anyway, which aligns you to the pole. If you are using an alt-az mount then levelling becomes important.

A "cage" doesn't seem very secure to me either...20,30kg suspended on 4 narrow bolts, kinda gets rid of the whole point of the pier!

Reply With Quote
  #3  
Old 08-03-2018, 06:28 PM
billdan's Avatar
billdan (Bill)
Registered User

billdan is offline
 
Join Date: Mar 2012
Location: Narangba, SE QLD
Posts: 1,072
Big argument on Cloudy Nights at the moment, on this subject.

Here is the link if you want to be more confused.

https://www.cloudynights.com/topic/6...ot-vibrations/

Cheers
Bill
Reply With Quote
  #4  
Old 08-03-2018, 07:00 PM
Merlin66's Avatar
Merlin66 (Ken)
Spectroscopy Wizard

Merlin66 is offline
 
Join Date: Oct 2005
Location: St Leonards, Vic
Posts: 6,237
Simon,
I built an extended pier for a NEQ6 pro head. I used a SW extension and used a central bolt to “lock” in to the top of the pier.

It’s been in action for the last two years, no issues, no drama.
Reply With Quote
  #5  
Old 08-03-2018, 07:28 PM
SimmoW's Avatar
SimmoW (SIMON)
Adapter Collector

SimmoW is offline
 
Join Date: Jan 2014
Location: Tamleugh, Victoria, Australia
Posts: 1,273
Sorry Ken, so you mean you haven't used a cage?

Thanks a heap Bill, I think!

I must read it in any case, esp to convince myself of advantage of the equatorial mount
Reply With Quote
  #6  
Old 08-03-2018, 07:53 PM
glend (Glen)
Registered User

glend is offline
 
Join Date: Jun 2013
Location: Lake Macquarie, NSW
Posts: 4,696
There are a lot of piers around with cages of some sort. If you are pouring your own concrete pier the placement of the J bolts and angular spacing may not be very precise. A cage used in that situation provides a good way of presenting a load equalisation platform for your mount adaptor. Of course extreme cages are not a good idea, and mine is minimal height off my poured pier. Levelling is not important for EQs but good weight distribution and support is important. There are hundreds of piers with cages, and as long as they are designed to support the equipment used they are ok. That said, cages should not be used as pier extensions imho, there are better choices (like pipe sections).
Reply With Quote
  #7  
Old 08-03-2018, 08:11 PM
Merlin66's Avatar
Merlin66 (Ken)
Spectroscopy Wizard

Merlin66 is offline
 
Join Date: Oct 2005
Location: St Leonards, Vic
Posts: 6,237
Simon,
No cage. The SW extension bolted directly to the pier then the NEQ6 head to the top.
No issues, no drama.
It currently holds a C11 and spectroscope etc.
Reply With Quote
  #8  
Old 08-03-2018, 08:50 PM
h0ughy's Avatar
h0ughy (David)
DOGHOUSE REBORN

h0ughy is online now
 
Join Date: Apr 2005
Location: NEWCASTLE NSW Australia
Posts: 30,046
so this pier has everything wrong going for it http://www.iceinspace.com.au/forum/a...e.php?a=201477

and http://www.iceinspace.com.au/forum/a...e.php?a=201478

http://www.iceinspace.com.au/forum/a...e.php?a=201478
Reply With Quote
  #9  
Old 08-03-2018, 09:05 PM
Merlin66's Avatar
Merlin66 (Ken)
Spectroscopy Wizard

Merlin66 is offline
 
Join Date: Oct 2005
Location: St Leonards, Vic
Posts: 6,237
No, I'm not saying that....just that a SW pier extension mounted on a central M12 x 1.75mm bolt works just as well.
Attached Thumbnails
Click for full-size image (Mainsail Obs 001s.jpg)
64.7 KB116 views
Reply With Quote
  #10  
Old 08-03-2018, 10:05 PM
LostInSp_ce's Avatar
LostInSp_ce
Registered User

LostInSp_ce is offline
 
Join Date: Mar 2017
Posts: 254
That's a nice setup Ken and the Nintendo controller is a nice touch. Simon I'm currently in the same boat as you but with the advice of a very helpful member in here this is what I decided to do. It's an old gas pipe with a cut out to allow the tightening of the adaptor plate bolts. Hopefully it will serve me well for years to come. The next step is figuring out what type of observatory to build around it
Attached Thumbnails
Click for full-size image (observatory pier.jpg)
102.3 KB91 views
Reply With Quote
  #11  
Old 09-03-2018, 11:31 AM
Kunama (Matt)
MSO Vagrant

Kunama is offline
 
Join Date: Sep 2012
Location: Garran, ACT
Posts: 3,464
The 'rat cage' is fine provided that you use decent sized plate and bolts and keep it as short as possible.

I built a 1200mm high pier for Phil's observatory using 220mm OD pressure pipe with a 9.5mm wall thickness. The base plate measured 350mm square by 16mm thick. The top plate and adapter plate are 12mm thick steel. The adapter plate is installed with M16 stainless steel bolts and sits only about 50mm above the top plate.

This pier weighed a mere 85kg and carries an EM400/Mewlon300 etc, it does not move....
Reply With Quote
  #12  
Old 09-03-2018, 01:08 PM
doppler's Avatar
doppler (Rick)
Registered User

doppler is offline
 
Join Date: Nov 2012
Location: Mackay
Posts: 1,390
Apparently mine setup is completely unsuitable in all aspects. A single wheelbarrow full of concrete for the footing (no reo), a 1200mm high pier with 1.5mm thick walls (sand filled), a rats cage with m10 bolts and a 10" newt (15kgs with full kit) on a Heq5 pro.
This is doing everything wrong and should be vibrating like crazy according to some experts ,so I'm puzzled as to why it works so well. The only vibration I can notice is from the wind, fortunately when it's clear here it's usually very still. My ground is hard packed sandy decomposed granite so there is no vibration coming up through the pier.
Attached Thumbnails
Click for full-size image (pier mounted.jpg)
198.9 KB92 views
Reply With Quote
  #13  
Old 09-03-2018, 01:28 PM
I.C.D (Ian)
Registered User

I.C.D is offline
 
Join Date: May 2006
Location: Wattle Ponds via Singleton
Posts: 409
Quote:
Originally Posted by SimmoW View Post
Hi folks, I'm thinking of getting a pier custom built by a trusted contact.

Many ppl use a cage to fine tune levelling. This concerns me due to possible flexure. Are my concerns valid? Is it possible to have a perfectly horizontal base? Does it matter nowadays if it's not perfectly level?

Thanks in anticipation of any comments/ideas.
Hi Simon I take you are talking about a base for a pier ,if you check this site out I have seen one of those over at Ilford last year the one they put was equal to 4 cubic meters of cement and if you move house you can reclaim it and take it with you
Ian
https://surefootfootings.com.au/
Reply With Quote
  #14  
Old 09-03-2018, 02:05 PM
traveller's Avatar
traveller (Bo)
Not enough time and money

traveller is offline
 
Join Date: Aug 2011
Location: Melbourne
Posts: 2,057
As others said Simon, no need for perfect leveling every time, so a cage free pier should be fine.
I have a similar setup as Ken's see this thread http://www.iceinspace.com.au/forum/s...d.php?t=136618
Bo
Reply With Quote
  #15  
Old 09-03-2018, 02:47 PM
OICURMT's Avatar
OICURMT
Oh, I See You Are Empty!

OICURMT is offline
 
Join Date: Apr 2010
Location: Laramie, WY - United States of America
Posts: 1,383
Quote:
Originally Posted by billdan View Post
Big argument on Cloudy Nights at the moment, on this subject.

Here is the link if you want to be more confused.

https://www.cloudynights.com/topic/6...ot-vibrations/

Cheers
Bill
Which in turn references... http://www.iceinspace.com.au/forum/s...d.php?p=855252
Reply With Quote
  #16  
Old 09-03-2018, 03:42 PM
AndrewJ
Registered User

AndrewJ is offline
 
Join Date: Mar 2006
Location: Melbourne
Posts: 1,872
Been watching this thread and the one on CN.
The whole problem is moot unless you have something that will cause "resonant" vibrations in the first place, ie wind, mount motor or ground based, and you need to define that first.
Dealing with an "oops i bumped the mount" moment cannot be handled by any sort of mounting ( and is not cost effective )
Also you need to look at the problem as an entire chain, and doing vibration analysis on something like that is soooooooooooo difficult in theory, as to be almost impossible.
In my case, if i have my 10" Meade LX200 on a wedge, a rat cage would be the least of my problems.
The only way to truly "test" if you have problems with your "entire setup" would be to fit a few accelerometers onto the bits and see what they report. Accelerometers are cheap as chips these days.
Also, as to requiring a large mass in the ground, i dont always think thats best, esp if you have ground vibrations.
To me, if you got a long piece of pipe and a hole borer/auger,
you could bore down say 2 metres and drop in the pipe and then backfill.
Its not going anywhere, and also has a much lower footprint for transmitting ground pressure changes ( moisture change or vibrations ) to it.
Have attached a piccy of an early pier i did this way with wood.
The hole i made was limited by my shovel size, but an auger would have been better. It never moved until it started rotting
an old telgraph/electricity pole would be perfect

Andrew
Attached Thumbnails
Click for full-size image (5 Hole Cleaned out.JPG)
36.6 KB66 views
Click for full-size image (6 Pier Pre fitting.JPG)
58.1 KB75 views
Click for full-size image (7 Pier Fitted.JPG)
80.8 KB62 views
Reply With Quote
  #17  
Old 09-03-2018, 11:14 PM
h0ughy's Avatar
h0ughy (David)
DOGHOUSE REBORN

h0ughy is online now
 
Join Date: Apr 2005
Location: NEWCASTLE NSW Australia
Posts: 30,046
can i add something else to the mix, please have a look at this link to an image provided by Martin Pugh now look at the base of the whole setup?

http://www.iceinspace.com.au/forum/a...e.php?a=224876
Reply With Quote
  #18  
Old 10-03-2018, 05:22 PM
SimmoW's Avatar
SimmoW (SIMON)
Adapter Collector

SimmoW is offline
 
Join Date: Jan 2014
Location: Tamleugh, Victoria, Australia
Posts: 1,273
Thanks for all the ideas and theory everyone! Can't see much reason for a cage at this stage
Reply With Quote
  #19  
Old 17-04-2018, 06:40 PM
el_draco's Avatar
el_draco (Rom)
Politically incorrect.

el_draco is offline
 
Join Date: Apr 2009
Location: Tasmania (South end)
Posts: 2,287
Quote:
Originally Posted by SimmoW View Post
Hi folks, I'm thinking of getting a pier custom built by a trusted contact.

Many ppl use a cage to fine tune levelling. This concerns me due to possible flexure. Are my concerns valid? Is it possible to have a perfectly horizontal base? Does it matter nowadays if it's not perfectly level?

Thanks in anticipation of any comments/ideas.
So, you spend a fortune building a really solid pier, bury it in a ton of concrete and then hang all your gear on 4 bolts and few nuts?

Its stating the bleeding obvious that this is not a good idea. You effectively negate all the effort below the rats cage. As someone else said, get the top of the pier pretty level and use the equatorial head adjustments to fix the rest.
Reply With Quote
  #20  
Old 17-04-2018, 07:39 PM
RobF's Avatar
RobF (Rob)
Mostly harmless...

RobF is offline
 
Join Date: Jul 2008
Location: Brisbane, Australia
Posts: 5,333
Quote:
Originally Posted by Kunama View Post
The 'rat cage' is fine provided that you use decent sized plate and bolts and keep it as short as possible.

I built a 1200mm high pier for Phil's observatory using 220mm OD pressure pipe with a 9.5mm wall thickness. The base plate measured 350mm square by 16mm thick. The top plate and adapter plate are 12mm thick steel. The adapter plate is installed with M16 stainless steel bolts and sits only about 50mm above the top plate.

This pier weighed a mere 85kg and carries an EM400/Mewlon300 etc, it does not move....
+1
Decent bolts and plate not set too high is fine for EQ6 style loads. Its nice to have easy access to lower bolt. Vibrations very likely far less than tracking and seeing errors for 99.99% of people.
Reply With Quote
Reply

Bookmarks

Thread Tools
Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +10. The time is now 12:29 PM.

Powered by vBulletin Version 3.8.7 | Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
Advertisement
SkyWatcher WiFi Adaptor
Advertisement
Interest Free Finance
Advertisement
Lunatico Astronomical
Advertisement
Bintel
Advertisement
Atik Horizon
Advertisement
NexDome Observatories
Advertisement
SkyWatcher 2018 Catalogue
Advertisement
FLI Cameras and Imaging Accessories
Advertisement
OzScopes Authorised Dealer
Advertisement
Astronomy and Electronics Centre
Advertisement